U.S. Pat. No. 4,452,808 discloses 4-aminoalkyl-indol-2-one derivatives having a selective D2 receptor activity. These compounds can be used for the treatment of hypertension. One of the compounds provided by this patent, namely 4-[2-(di-N-propylamino)ethyl]-2(3H)-indolone, is used for the clinical treatment of Parkinson disease.
European patent No. 281,309 provides indol-2-one derivatives carrying an arylpiperazinyl-alkyl substituent in position 5, which can be applied for the treatment of psychotic conditions. One of the compounds described in this patent, namely 5-[2-[4-(1,2-benzisothiazol-3-yl)-1-piperazinyl]-ethyl]-6-chloro-1,3-dihydro-2H-indol-2-one, exerts its activity by interaction with D2, 5-HT1A and 5-HT2 receptors and is used in the clinical treatment as an antipsychotic agent.
European patent No. 376,607 discloses indol-2-one derivatives substituted in position 3 by an alkylpiperazinyl aryl group, which exert their activity on 5-HT1A receptors and are useful for the treatment of central nervous disorders.
In the international patent application WO 98/008816 indol-2-one derivatives containing a substituted alkyl-piperazinyl, substituted alkyl-piperidinyl or alkyl-cyclohexyl group in position 3 are disclosed. These compounds possess psychotrophic activity.
The acceleration of technical-social development in the XX. century constitutes a permanent compulsion of adaptation for humans, which, in adverse cases, my lead to the occurrence of adaptation disorders. Adaptation disorders constitute an important risk factor in the development of diseases of mental or psycho-somatic origin, such as anxiolytic syndrome, stress disorder, depression, schizophrenia, disorders of the sense organs, gastrointestinal diseases, cardiovascular diseases, renal disorders.
For the treatment of the above clinical patterns most widespreadly pharmaceuticals exerting their activity on the benzodiazepine system (e.g. diazepam) or on central 5-HT1A receptors (e.g. buspiron, ziprasidon) have been applied. In case of psychosomatic diseases anxiolytic therapy is often complemented by the administration of pharmaceuticals possessing antihypertensive (acting on the α1 or α2 receptor), or antiulcer (H1-receptor antagonist) activity.
Anxiolytics of benzodiazepine type are accompanied, however, by several unpleasant side-effects. They have a strong sedative activity, cause decline of the power of concentration and memory and possess muscle relaxant effect. Said side-effects influence the quality of life of the patients in an adverse manner restricting the scope of application of such pharmaceuticals.
The pharmaceuticals acting on the 5-HT1A receptors that have been so far applied in the therapy are accompanied, however, by several drawbacks and undesired side-effects. It is a drawback that the anxiolytic effect can be achieved only after a treatment lasting for at least 10-14 days. Besides, after the initial administration an anxiogenic effect occurs. As to the side-effects, the occurrence of sleepiness, somnolence, vertigo, hallucination, headache, cognitive disorders or nausea has often been observed. Such effects of the pharmaceuticals render the co-operation between physicians and patients much more difficult, because the patients are in the belief that the worsening of their symptoms is a consequence of the drug administration.
Beside the stress occurring during adaptation to the environment another great problem of modern societies is the rapid ageing of population. Owing to the results of modern medical science life expectancy has increased, and the diseases occurring due to ageing or developing in the declining years, particularly the number of mental diseases has grown in leaps and bounds. The solution of the treatment of Alzheimer's disease, vascular dementias and senile dementia has become a social problem.
Another consequence of ageing processes is the considerable increase in the number of auditory disturbances. According to WHO statistics, in 2001, 250 million people suffered from moderate or severe auditory dysfunction. Senile auditory disturbances can be evidenced in 10% and 25% of the 45-55 year old and 65-75 year old population, respectively.
As a result of the enumerated processes there is a strong need for new and efficient pharmaceuticals ensuring a more effective treatment of these diseases than those available for the time being.